find the stationary points of the following function f(x)=x^3-3x^2-24x-7

Answer 1

The stationary points are where df/dx = 0
So solve
3x^2 -6x -24 = 0
which is equivalent to
x^2 -2x - 8 = 0
(x-4)(x+2) = 0
That tells you you the two x values where the function is zero.